PROMPT ACTIVATION OF TELOMERASE BY CHEMICAL CARCINOGENS IN RATS DETECTED WITH A MODIFIED TRAP ASSAY

The maintenance of telomere length is crucial for survival of cells. T elomerase is an RNA-containing reverse transcriptase, which is respons ible for elongation of shortened telomeres. Telomerase reactivation ha s been suggested to be involved in malignant progressions. To study on the involvement of telomerase activation in in vivo carcinogenesis, w e first modified the original TRAP assay by changing the primer design s and the labeling method of PCR products to an end-labeling method. S econd, we investigated the activation of telomerase in differ ent orga ns after treatments of rats with various chemical carcinogens. Very ea rly after the beginning of the treatment, telomerase activity in the l iver, kidney, and lung was increased. In most cases, telomerase activa tion occurred in the primary or favorite target organs. The present re sults suggest that telomerase activation occurs promptly when animals are exposed to chemical carcinogens, which may contribute to ire vivo chemical carcinogenesis. (C) 1998 Academic Press.